W&T RS232 88102, RS232 88257, RS232 88256, RS232 88410, RS232 88409 User Manual
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W&T
RS232 Serial Buffer
Subject to error and alteration
Manual
RS232 Serial Buffer
Models 88102
88256
88257
88409
88410
Release 1.0
W&T
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W&T
RS232 Serial Buffer
© 12/2002 by Wiesemann & Theis GmbH
Subject to errors and changes:
Since we can make mistakes, none of our statements should be
used without checking. Please let us know of any mistakes or
misunderstandings you are aware of, so that we can recognize
and eliminate them quickly.
Perform work on and with W&T products only as described here
and only if you have read and understood the manual fully. Unauthorized use can result in hazards. We are not liable for the
consequences of unauthorized use. When in doubt, check with
us or consult you dealer!
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W&T
RS232 Serial Buffer
Subject to error and alteration
RS 232 Serial Buffer
W&T RS232 Serial Buffers are used for fast buffering of serial
data between an RS232 data transmitter and RS232 receiver.
Function
The buffer works bi-directionally at a maximum transmission
rate of 115.2kbps and allows separate configuration of the input and output port with respect to transmission speed, data
format and handshake procedure. In the direction of the receiver the entire memory capacity minus the reverse channel
capacity of 4kB is available. This memory is reserved for buffering data from the peripheral to the computer.
Configuring the buffer
Before starting up for the first time, the buffer ports must be
configured for the desired transmission parameters.
Serial parameters
On the rear side of the buffer are three DIL switch blocks, with
the center (S2) block used for configuring the input port and
the right (S3) block the output port. The assignments for these
two DIL switch blocks is identical and can be found on the part
label. The ability to configure both ports separately permits you
to work on the computer side with a significantly higher transmission speed than the peripheral allows. This can drastically
increase the efficiency of the buffer.
In addition, you can use the buffer as a converter between two
RS232 devices whose transmission parameters or handshake
procedure are not otherwise compatible.
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W&T
RS232 Serial Buffer
Modes
In standard mode (S1.8 = „off“) the RS232 Serial Buffer functions like a data buffer using a FIFO principle. The data leave
the buffer on the output in exactly the same order as they were
written to the buffer by the computer. Pressing the „copy“ key
in this mode causes the entire buffer contents to be output
again, whereas „reset“ clears the buffer contents.
In block mode (S1.8 = „on“) the computer can write as many
data blocks as desired to the buffer, which the buffer then administers as separate print/plot jobs. The buffer recognizes the
end of a data block from a pause in the transmission of at least
15 seconds. Each individual job can be output as often as desired by pressing the „copy“ key. The „next block“ key activates
output of the next stored job. After outputting one data block,
the buffer stops outputting until the „copy“ or the „next block“
key is pressed. The „reset“ function clears the buffer contents
in this mode as well.
Pin assignments and buffer connection
The input of the buffer is implemented as a 25-pin SUB-D
socket using DTE, so that as a rule the printer/plotter cable already present between the computer and buffer can be used.
The buffer output uses a 2m long serial cable with a 25-pin
SUB-D male using DCE at its end, which in most cases can be
plugged directly in to the peripheral.
In a very few cases it may be necessary to jumper pins 5 and 6
inside the 25-pin SUB-D male connector. An example for connecting the buffer to a 9- and 25-pin PC and to a plotter is
shown in the illustration below:
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